The Monster Association is a fictional group from the popular manga and anime series One Punch Man. This organization is made up of various monsters and villains who unite to challenge the heroes of the world. Their goal is to create chaos and prove that monsters are superior to humans. Led by the powerful monster Orochi, the association recruits many unique and dangerous creatures, each with their own abilities. They often clash with the Hero Association, which consists of brave heroes like Saitama and Genos, who strive to protect humanity from these monstrous threats.